1. Field of the Invention
The invention relates to medical devices with a surface exposed in particular to the surrounding environment, and in particular a microscope, preferably a surgical microscope and/or its support. Explicitly not comprised in the invention are non-optical instruments for invasive interventions. Included, on the other hand, are optical devices and instruments like, for example endoscopes, laser scalpels, etc., scalpels or medical implants, plastic heart valves or similar items.
2. Description of the Related Art
It has always been a goal during operations and/or in the area of medical research to work in as sterile a manner as possible. That means the patient to be operated on and/or the subject involved in research is as much as possible not to be contaminated by germs (bacteria, viruses, fungi, etc.). Moreover, by completely preventing or removing any impurities, in particular protein substances, allergic reactions by the patient can be prevented, should he accidentally or unprotectedly come into contact with the medical devices. This is normally achieved by meticulously cleaning or sterilizing the surfaces of the medical devices. Those surfaces that do not sterilize well are covered with sterile cloths or sheets. With the operating microscope a “drape” typically must completely envelop or screen the surface of the microscope and support, at least in the sterile area around the patient. A drape of this kind is described, for example, in the German patent specification DE-A1-44 13 920. The drape is as a rule a disposable article so that using it is also connected with costs and with a direct environmental impact. The disposal of disposable articles from an operating room is expensive.
Aside from the fact that the covering and sterilization of the contaminated material, not to mention its disposal, is a time-consuming and costly process, there is always the danger of remaining unsterile gaps. Moreover, drapes as a rule reduce the optical qualities of microscopes, since they necessarily also enclose the lens along with the other parts. The cover glasses used for this can only be poorly steam-sterilized. Moreover, the covers restrict freedom of movement and visibility in the sterile area.
Olympus has brought microscope models CHK2 and CHL2 on the market, the optical parts of which are continually overflowed during manufacture with a thin vaporous antifungal gas that effectively prevents the growth of funguses for a period of three years. A tightly sealed binocular body is even more extensively protected against the onset of fungus because neither impurities nor moisture can intrude into the microscope. This antifungal arrangement involves a protection of the optical parts since fungus often leads to damage of the optical parts of a microscope, especially in tropical regions. In this respect the antifungal coating of the lens provided by Olympus is an improvement, but the sterility of the microscope is not improved. Only the service life of the lens or its optical characteristics are extended. The protection of patients was not within the purview of the producer for this type of antifungal outfitting.